On Tue, 20 Nov 2007, Frans Pop wrote:
> A patch is available, but the question facing Debian is: should we do a scan
> of the archive to see if and which binary packages are affected?

Given the sort of insiduous, nightmarish to debug kind of bug this thing
could cause, I'd say that yes, we should. I don't expect it is a very
common problem, but one can't be sure without looking for it.

Also, we should push updated gcc packages to all suites.

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them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh


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* Frans Pop <elendil@planet.nl> [2007-11-21 17:47]:
> The most effective/efficient way to do this may be an archive rebuild with
> a modified gcc that emits a warning if this case is hit and then check build
> logs for the warning.
>
> Something like the patch below (stolen from the thread on linux-kernel).

Sounds like something Lucas (CCed) could do.

> --- trunk/gcc/fold-const.c 2007/11/17 13:46:53 130257
> +++ trunk/gcc/fold-const.c 2007/11/17 14:22:42 130258
> @@ -6095,6 +6095,9 @@
> }
> break;
> }
> + /* If the constant is negative, we cannot simplify this. */
> + if (tree_int_cst_sgn (c) == -1)
> + { warning(0, "Unpatched gcc miscompiles this"); break; }
> /* FALLTHROUGH */
> case NEGATE_EXPR:
> if ((t1 = extract_muldiv (op0, c, code, wide_type, strict_overflow_p))

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Martin Michlmayr
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On 21/11/07 at 18:03 +0100, Martin Michlmayr wrote:
> * Frans Pop <elendil@planet.nl> [2007-11-21 17:47]:
> > The most effective/efficient way to do this may be an archive rebuild with
> > a modified gcc that emits a warning if this case is hit and then check build
> > logs for the warning.
> >
> > Something like the patch below (stolen from the thread on linux-kernel).
>
> Sounds like something Lucas (CCed) could do.

I'm currently in VAC. I could start a rebuild on monday if someone
provides patched gcc packages for i386 for me.
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| Lucas Nussbaum
| lucas@lucas-nussbaum.net http://www.lucas-nussbaum.net/ |
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